Nightsound Studio "production reel" icon set

Developed this icon set for a recording studio's production reel/promotional sampler. The four, which represent (L to R) elements of the studio: production, engineering, distribution, and artist development/growth. They're an expansion on the existing icons used in their logo which include four phases of the moon. Still not sure what the album design will look like from here though... How do these read to you all?